1. Field of the Invention
The present invention relates to nozzles and injectors, and more particularly, to swirlers for nozzles and injectors in gas turbine engines.
2. Description of Related Art
In a fuel nozzle for a gas turbine engine, compressor discharge air is used to atomize liquid fuel. More particularly, the air provides a mechanism to breakup a fuel sheet into a finely dispersed spray that is introduced into the combustion chamber of an engine. Quite often the air is directed through a duct that serves to turn or impart swirl to the air. This swirling air flow acts to stabilize the combustion reaction.
There are many ways to develop swirl in a fuel nozzle. Historically, helically vaned swirlers 1, as shown in FIG. 1, were used because of their ability to effectively turn the air flow. These helical vanes 2 generated acceptable air flow characteristics for many engine applications. Helically vaned air swirlers are traditionally placed upstream 5 in the internal air path 4 of a nozzle 3. Fuel injected into the swirling flow is mixed with air for combustion downstream 6.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for a swirler that allows for improved control of wake and air sheath thickness, a larger mass flow rate while maintaining desired swirl, reduced weight and reduced pollutant emissions, including NOR. There also remains a need in the art for such a swirler that is easy to make and use. The present invention provides a solution for these problems.